Treatment of gases.



H. D. RANKIN.

' TREATMENT OF GA SES. APPLIUATION FILED JULYG, 1909.

Patented Mar. 25, 1913'.

2 SHEETS-SHEET 1.

H. D. RANKIN.

v TREATMENT OF GASES. APPLICATION FILED JULY 6, 1909.

1,056,830,. Patented Mar. 25, 19 13.

2 SHEETS-SHEET 2.

IFWZ

Witnesses:

. To all whom it may concern UNITED STATES PATENT OFFICE.

HABRYD. RANKIN, or JULIET, ILLINOIS, ASSIGNOR-TO AMERICAN NZ'UIROGEN COMPANY, a conrol'wrxon or rumors.

- TREATMENT OF eases.

Be it kn'ownjthat'. I, HARRY D. RANKIN, a. citizen of the United States, residing at Joliet, in the county of Will and State of Illinois, have invented certain new and useful .'Improvements inthe Treatment of Gases, of which the following is a ,full,

clear, concise, and exact. description, .refer-;

ence beinghad to the accompanying drawings, forming a part of this spec1ficat1on.

My invention relates to the treatment of gases and has particular reference to ap paratus used for combinin -.any' mixture-of nitrogen and: oxygen an the subsequent absorption of'the' gas thus formed, in order to. produce compounds of nitrogen, e. g.

. nitricacid.

I am aware that many attemptshave been made to produce compounds of nitrogen,

c. g. nitric acid from mixtures of nitrogen and oxygen, 6. g. air, but hitherto these attempts have proved unsuccessful from a commercial point of view, either onaccount of the inoperativeness of the process itself or on account of'the excessive cost of carrying on the operation. In my invention I pass the compressed gases into and out of an otherwise hermetically sealed furnace and inside of this furnace the mixture of oxygen and nitrogen is subjected tothe action of'an electric arc and the following characteristic reactions take place:

. Besides the xids formed by the above rcactions, other ower oxids may be formed as N 0, N 0,, etc. The exactnature of these and, in order to fixthe oxids, I have found it necessary toj'immediately co0l. the'gases which result from the above mentioned-reactions. These gases are conducted from the combining turn-acethrough water cooled pipes to a mixing chamber where, if neces sary, additional oxygen, e. flq'wby th'e addition of air, may be provided'in order to bring about reaction (2) rovided' it has not already takenfplace in tliefurna'ce.

Specification of Letters Patent. a ntetion'm a m e; 1909. Serial No; 506,044.

. tower to tower bein .were employed.

Still another feature consists in the use 85 4 Patented Mar. 25', 1913'.

The mixing chamber may also be used as a dust trap to catch thesmalljparticles of .dust from the lining of said, furnace and from the electrodes which. come from the combining furnace. From the mixing chamher, the gases pass to absorption towers which-are filled with water.

absorption of the oxids of nitrogen, the

gases are preferably passed through several towers, the order of v their change at' intervals when the nit'ric-aci from any one tower has reached the strength'which it is desired to manufacture. The: acid is then drawn otf from the tower and fresh water added.

II have found: that in place of; usin mixing chamber, which also acts as a net trap, the dust from the furnace may be caught in the first tower.--

Another feature of my invention consists in preheating the air by meanscof passing it throu hja coil which encircles the "com-' bining urnace. In this way it 'is' possible The reaction passage from to bring about the combining action much quicker-than would be the'case if cold gases of other gases" or liquids, e, g. methane,

- a, steam, etc., and of special electrodes, the upper electrodes being constructed of any suitable material, e. g.-ir'on-or steel, and suitably cooled, whereas the lower electrode consists of a suitable'composition, e. g. of calcium cal-bid, the magnetic oxid of iron and the oxids of copper, chromium, nickel, uranium, titanium and "ana'dlum, WhlCh 1s artly urmgmelted by the action of the arc and the operation of the furnace remains partly in a molten condition. The action of these gases, vapors, liquids and special electrodes is important inasmuch as they causethegas to be ionized and as a result of such ioniza- '-tion the electrical resistance between the considerable importance inasmuch as the mixture of oxygen and nitrogen introduced.

in the furnace chamber is generally under a pressure of from three'to ten atmospheres,

and without the ionization the resistance between the electrodes and interacting molecules would be increased to an .undueuextent; whereas, with thesaid fluids and electrodes the speed of the reaction is greatly increased.

The are formed between the electrodes extends to aconsiderable distance beyond the ends of the electrodes. the gases passing through the combining chamber of the furnace should not flow too rapidly as under such circumstances the arc would be blown out and, on the other hand, it must not flow too slowly as" in the latter case, the combined oxide of nitrogen would not be cooled sufliciently soon to prevent dissociation.

An advantage of considerable importance arising from the construction of my furnace is that on account of having the gases in the combining chamber under considerable pressure, if apunctur'e occurs in the water cooled electrode, the water will not escape through thisepuncture into the chamber but the ressure causes the water toback up an the combinin chamber istherebykept from any danger o flooding.

, It is, of course, necessary that the two electrodes should 'be-e'ntirely insulated' from each other-and inorder to accomplish this the metallic work of the furnace is provided with insulation as willbe described in detail hereinafter. The conditions of insulation are somewhat diflicult to be met and it is largely "to render this insulation easier that the gasis passed through suitable driers before it enters the combining chamber of the.

furnace.

These and other advantages of my system will be more apparent by reference to the drawings, in which- Figure l is adiagrammatic elevation of my complete system, Fig. 2 is a vertical sec- .tion of the combining furnace, Fig. 3 is a view on the line 3-3 of Fig. 2, and ig. 'is a sectional view on the lifieA- i of F g. 2.

Inorder to'understand more readil 'the operation of my system as --a whole,

will first describe thedetailed construction of the combining furnace as shown in Figs. 2, 3 and 4. The'combining chamber '1 is surrounded by a, wall 2 of refractory material.

For this purpose ,I prefer to use magnesite,

bauxite, chrome or someother'form of mate-- rial which has extremely refractory properties, this feature being necessary on account of the high temperatures which are attained b means of the arc. The lower part 3 of a t e wall 2 is of somewhat smaller diameter than the main chamber of the furnace, as will be described'more in detail hereafter. Outside of the walls 2 and 3, is a second layer of refractory material 4 or fragments of such material- Outside of the layer 4 is a coil 5 through which the mixture of oxygen It is important that in turn, rest on the and nitrogen, e. g. air, is introduced to the furnace, the gases entering at the upper portion 6 of the coil, and being delivered to the lower part -of the combining chamber through the portion 7. Outside of the coil 5 is the iron or steel shell 8, to which is riveted a steel top 9. The bottom of the furnace is similarly provided with a steel plate 10 which is suitably riveted to the'shell 8.

In the 'lower portion of the combining chamber 1 is provided the lower electrode 11, this electrode consisting of a refractory cup 12 in which is placed the, readily fusible composition 13. A perforation is provided in the bottom of the cup 12 through which the conductor 14 is brought into contact with the composition 13. The lower part of the combining chamber 1 issealed by means of a blockof insulating material 14" through which the conductor 14' passes. The'up'per electrode '15 is constructed of any suitable material, e. g. iron or steel alone or charged with the material of the upper elect-rode, and

is suitably cooled. A pipe 16 is provided-on its lower end with a rounded head or extension 17, the inside of which is continuous with the inside of the pipe 16. Within the pipe 16 is provided a second smaller pipe 18.

It is clear that any cooling medium may be introduced in the pipe 18 throu h the pipe 19 and that after passing through the extension 17, this cooling medium will flow upwardly between the outside of the pipe 18 and the inside of the pipe 16, and will then be carried away through the outlet 20. An electrical connection may be made on any point of the pipe 16 with the opposite terminal of the source of current to that with which the conductor 14' is connected; Attached to the upper part of the pipe 18 is a rack 21 movable in-a vertical plane by means of a pinion 22 which is rigid y connected to the disk 23 on'which is mounted a'handle not shown in the drawings. A rotary guide 24 serves to hold therack '21 in 'engagement with the pinion 22. Inasmuch as the pipes 16 and 18 are rigidly connected, it is evident that the electrode15 may be moved-as a whole in a vertical plane. I Y

The top of the furnace 9 is'provided with a. gasket 25 of insulating-material on which rests the circular plate 26, 'rovided with an opening as will be described hereafter. The

' plate'26 is securely held in position by meansof clamps 27 which engage pieces of insulatas, for example, mica, which ing material 28,

late 26. The horizonta member 29 of the 0 amp 27 may be adjusted by turning the nut v30. It is clear that. by this construction the plate 26 is electrically insulated from the shell 8 and the top 9 of the furnace.

Passing through the opening of the plate 26 is the cooling apparatus for the gases passing out of the furnace. This cooling '35 electrode 15. This space 43 connects directly mechanism consists of an outer shell 31 and an inner shell 32, the lower portions-of these two'shel ls being sealed by'means of the angle 1rons'33. The space between the'upper portions of these-two shellsis allowed to remain open. lg tlreportion above "the furnace t e outer shell 31 is interrupted and a con ling 34 is inserted. Late'rallyeXtendrough which passes a smaller pipe 36 which connects'with the inside of the inner shell 32. The space between the outer end of the pipe and thepipe 36. is sealed by theportio'n 37. An outlet pipe 38comm'uhicates through the pipe 35 with the space be,- tween the pipes 35 and 36. Av pipe 39 is introduced in the space between the outer shell 31 and the inner shell 32 and. passes downwardly to a positionnear the lower edges --iplg rom this coupling is the pipe 35 of these shells. It is now clearthatif water '1s introduced through the pi" 39, it -will fillthe space between the she Is 31 and 32 and the space between the pipes 35 and 36 will then pass through'the outlet 38.

The electrode 15 is adapted to move within a bearing which is composed of a collar 40 which fits within a second collar 4-1. Be-' tween these two collars is placed packing 42 so that it is impossible for gases to escape from thefiir'nace between the pipe 16 and the'colla'rs 4Q and-412, The inner shell 32 is securely attached to the lower collar 41. It

, is clear from the construction which we have describ that there is a space between the. inner shell 32 and the outer pipe 16 of the with the interibr of the combining chamber 1. It is evident that if gases under pressure are contained in the chamber 1, they will pass outwardly through the space 43 and the pipe 36. During this passage through the vention.

space'43 and the pipe 36, the outgoing ases are subjected to the cooling action 0' ,the cooling'medium, e. 9. water, flowing between the outer shell 31 and the inner shell 32. i'and between the pipes 35 and 36. The gases are thus im'medlatel' cooled after leaving the combining cham er 1, which is a feature of great importance in the operation of my in- Hating described the detailed construc-v tion oiimy furnace, I will now deal with the operation of in system as a whole, as dia-.'

f grammatically lllu'strated in Fig. 1.

A is, an aircomp-ressor which connects by means of the pipe 44; with the mechanical drier B. As] the compressed fluids e. g. mixturejofoxygen and. nitro on, such as air,

enters thedrier B, it 'imme iately expands with .the result that the moisture. is precipitated from the air, this moisture being eriodically drawn ofi through the stopcoc 45.

If desired, a second drier 'B' may be connected with the first drier, by means of pipe 46 and additional mechanical driers may be used, if necessary. From the last me- I chanical drier, the air passes through the f pipe 47 to the bottom of the chemical drier "G, the interior of this drier being provided with a series ofshelves 48; on which is placed lime'49, 'or other desic eating K181161131. The air next passes, from the upper part of the drier 0 through the pipe 50. This pipe is provided with an electrical insulating section 51. The mixture of oxygen and nitrogen, e. 9'. air, next asses through the pipe 6 and the heating coil 5 of the electric combining furnace D. The mixtu're of oxygen and nitrogen e. g. airenters the lower part of the combining chamber 1 through the portion 7 of the preheating coil '5, passes upwardly ast the lower electrode 11 into the principa portion of the combining chamber 1, and then u wardly between the upper electrode .15 and the inner shell 32, and then through the outlet pipe 36 which is provided with an insulating section 52. The compound of oxygen and nitrogen found 6. g. oxid of nitrogen next passes through the pipe. 53 into 'themixing chamber E. into air may-be introduced through the pipe 54, if so desired. The mixing chamber E also acts as a dust trap and purifies the gases from dust and other impurities. The gases .next pass through the pipe-55 to the bottom of the absorptionchamber F, constructed of v wood which has been treated with melted parafiin, for example, by first boiling said wood in crude paraffin, whereby the greater portion of the resinous material is eliminated and then treating the said wood with refined paraflin, whereby it becomes coated with a thick layer thereof. Or, the wood may be so treated with any'other compound insoluble in'. nitric acid. The absorption chamber is filled with water in which are placed pieces of any suitable material, 3'. g. quartz 56 in order to more effectually break up the gases and-promote absorption-"The pipe 55 is provided inside of the tank with a wooden inclosing shell 57 so that the pipe may be readily withdrawn for repairs and again placed in position without disturbing the quartz 56. v

A sampling pipe '58 leads to the bottom of the absorption tank F and through the pipe a small quantity of water and its absorbed gases maly' be withdrawn at any time through the va e 59 for testing purposes. The unabsorbed portion of gases passes through the pipe-6O to a second absorption chamber F and from this chamber through a second pipe 60 to stillanother absorption 125 chamber. The number of these chambers may be multiplied as desired inorder to obtain a perfect absorption of the gas or gases. Suitable p 1 ing may be provided so that the gases wil enter any desired ab sorption tank' first and then pass to the 90 which additional oxygen 6. g. by means of others in any desired order. When the test shows that the water has absorbed the desired amount of nitric oxid, this tank is cutoff from the supply of "gases and the nitric acid is drawn off. It is then refilled with water and the absorptionprocess begins once more.

The current is suppliedto the combining furnace D from two electric mains 61 and' and is then gradually raised, the'length of the are thereby being increased. The mixture of oxygen and nitrogen, e. g. air from compressor A passes through the driers as described above and enters the lower portion of the furnace through the portion 7 of the coil 5. As ex lained above, itis im-- portant' that the mixture of oxygen and nitrogen should pass through the combining chamber 1 at such a rate that the oxids of nitrogen which are formed by the electric arc, come within the cooled shell 32 suiiicient-ly quickly so that the gases are not dissociated; while, on the other hand, the

"speed of the gases must not be such that the arc will be blown out by the faction of these ases.- It is clear in this connection that t e size of the combining chamber 1 with respect to the fluids passing therethrough and the size of the arc is of vital importance. The'fiuids must pass uniformly and steadily through the combinin'g chamher, in order not to blow out or disrupt the arc. Moreover, the chamber must be of such character that the mixture of nitrogen and oxygen passing therethrough will be subjected to the action of the arc. .The chamber mustnbe long or high enough to complete .the combining action, and not so long that there will be dissociation of the gases. As a matter ofjpractical experience, I have found that a combining chamber having a height of about '30, inches from the lower part of \the coolingshells 31 and 32 to the lower art of the wall 1, a diameter of 7 inches, a

istance between electrodes of not less than '3 inches, anoperating current of 100 amperes on a low tension circuit, gives satisfactory results. The oxids of nitrogen which have been fixed in the combining chamber. are immediately cooled by the action of the cooling medium, 6. g. water, between the shells 31 and 32 and also by the cooling medium, e. g. water, between the outside of nitric acid or nitrates, maybe used from that which I have described, many of such processes being well known in the art. In

the absorption apparatus I have found that it is advisable to use pipes which are but little affected by the action of the gases, as, for example, porcelain lined or aluminum pipes, which have been boiled in refined paraffin, preferably in a vacuum.

Many changes could be made in the-detailed construction of the apparatus which has been described above, without departing from the spirit of my invention.

a What I claim as new and desire to cover by United States Letters Patent is:

, 1. In apparatus for combining gases, the combination of a combining chamber, a coil surrounding and communicating with said chamber, said coil adapted to preheat the gases in their passage therethrough, electrical means for heating said gases within said chamber, and means for delivering said gases from said chamber.

' v 2. In apparatus for oxidizing a gas, the combination of an oxidizing chamber, a coil surrounding said chamber and communicating therewith, said coil adapted to preheat said gas and oxygen mixed therewith in its passage through said coil, electrical means for producing an arc within said chamber, means for delivering the gases from said chamber, and means for water cooling-saidgases-on their outward passage.

3. In apparatus for the treatment of gases, the combination of a combining chamber, an inlet for the gases into said chamber, a metallic electrode, a second metallic electrode adapted to form an arc with the first electrode, said second electrode adapted to become molten by the action of the arc, and an outlet for the gases from said combining chamber.

4. In apparatus for the treatment of gases, the combination of a combining chamber, means for introducing the gases into said chamber under pressure, means for retaining the pressure within said chamber, a

water cooled metallic electrode, a second electrode adapted to form an arc ,with said first elect-rode, said second electrode adapt'ed to become molten under the action of said are, and means for delivering the gases from said chamber.

5. In apparatus for oxidizing a gas, the

' I oxygen into said Chamber under pressure,

' 7. In apparatus for combining thenitro I said chamber, a water cooled metallic elecv trade, a second electrode adapted to form an a j combining chamber, means. for. preheating the all, means for introducmg the. preheat;- 40

chamber, a water cooled electrode within. said chamber, means for adjusting the position, of said electrode, a second readily fusi- 4 bleelectrode adapted to form a-flaming arc.

v heated air into said chamber under pressure,

' "with said first electrode, an outlet from said for the gases from said chamber. 1

combination of an. oxidizing chamber, an in- ,gases from said chamber, and means for trade adapted to become moltenwith a rise of temperature, means for delivering the I combined gases from said chamber,- and means for cooling said'gases on their up- 35 trogen and oxygen of air, the combination said chamber, means for adjustingthe position of said electrode, asecond readily fusion their-{outward passage.

readily fusible electrode adapted to form an arc with said first electrode, and an outlet 6. In apparatus for oxidizing a gas, th

let for introducing a mixture of said gas and means for sealing said chamber, a water cooled metallic electrode, a second readily fusible. electrode adaptedto form an .arc with said first electrode, an outlet for the cooling-the gases in their outward passage.

gen and oxygen of air, the. combination ofa combining chamber, an inlet for the air into ward-passage.- J

p .9, In apparatus forcombmmg the mtrogen and oxygen of air, the combination of a ed air into said chamber under pressure; means for retalmng the pressure wlthm sa d witlrsaid first electrode, and an outlet from said chamber.-

10. In apparatus- 'for combiningthe niofa combining chamber, means for preheat-. ing the air, means for introducing the premeans-for retaining the pressure within said chamber, a water cooled electrode within ble electrode adapted to form a-flaming arc" chamber, and means for cooling said gases 11. Inapparatus for combinin the nitrogen and oxygen of air, the comination of a combining chamber, a coil surrounding and-.comniunicatin with said chamber, said 0011 adapted to pre eat the air passed therethrough, means for introducing air underpressure through said coil to said chamber, means for retaining the pressure Within said chamber, a water cooled .me-tallicelectrode within said chamber, means for adjusting 'the position of .said electrode, a second fusible electrode adapted to form a flaming arc with=said first electrode, refractory'means for containing said fusible electrode, and means for delivering the gases from said chamber.

12. In apparatus for combining miachanically mixed gases, the combination of a c'ombmmg chamber,- vmeans for preheating said gases, means for exclusively introduc 'ing said preheated gases into said chamber under pressure, means forretaining the pressure w1th1n said chamber, a pair; of electrodes within said chamber,.s aid electrodes adapted to form between them a flaming are, means for electrically. insulating said velectrodes from each other, and a watercooled -out let from-said chamber.-

13. In a system for-combining gases, the combination of meansfor first compressing gases, means for then drying the gases,

means for'then preheating the gases, a. combining chamber, means for then delivering the gases to .said chamber under pressure, means for sealing said chamber, means for then subjecting said gases to the action'of an electric arc, and means for then deliver- 7 ing said gases from said-chamber 14,, In apparatus for combining gases, the combinationof a combining chamber, 'a coil surrouiiding andcommunicating with said. chamber, said: coil'adap'ted to preheat the gases in their passage therethrough, and

means for heating said gases within said chamber.'

ing therewlth, said coil adapted to-p'reheat; said gas and oxygen mixed therewith in its passage through saidcoib. and means for a heating said gases within said chamber.

16. In apparatus for treating gases, the a j combination of a chamber, an inlet into'said chamber, an electrode, a second' electrodegf, adapted to form an arc with said first elec-QQ:

'trode,,said second electrode adapted to be an outlet to: said chamber. a h I In witness whereof, I hereunto subscribe name this first dayof July, 1909. j v

"' v a HARRY n. RANKIN.

Witnessesi'f i EnsoN R. WOLCOTT v ERNEST'M. Droxnin' jcome molten under the action of the arc, anjdj v I I '15. In apparatus'for oxidizing a gas, the 5 combination ofan oxidizing chamber, a coil surrounding said chamber and communicat- 

